1. Field of Invention
This invention relates to equipment for adjustment of the height and tension of volleyball nets.
2. Background - Prior Art
Volleyball is becoming more popular in the U.S., with an increase in professional tournaments and prize money, including men's and women's beach doubles tournaments offering millions of dollars yearly. Court set-up is exacting for volleyball tournaments of all types, indoors and out, and for all courts where advanced players play and practice. The height and tension of the net is prescribed in the rules of play, and height is different for women and men. Therefore, net poles must provide means to adjust the net height and tension. Establishing and maintaining net height on sand courts is made more difficult by the uneven and changing level of the playing surface.
Many net posts are only adjustable in discrete steps, by selecting among fixed connectors on the posts. These types are very tedious and time consuming to adjust properly. Some have a winch for the upper net cord, making its tensioning easier, and some have a winch for the bottom cord as well. However, net height adjustments using these combinations are iterative because reconnecting and tensioning of each main cable and net-edge cord changes both the height of the net and the tension required of the other cables and cords. Thus, court set-up and gender change is difficult or inconvenient, due the limitations of net adjustment mechanisms.
Often, permanent posts in sand courts are not tall enough to provide proper net height. This can happen when court sand has been replenished, or through the shifting of sand toward the net by play wear. Net attachment points may have originally been at proper height, but later no adjustment can be made without court or post repair.
An expensive mechanism for indoor courts partially solves the adjustment problem by utilizing a telescoping net post, comprising a movable upper post inserted into a fixed bottom tube. Once net cord tension is adjusted, it need not be readjusted to change the net height. The whole upper portion of the post moves by turning a crank. This works reasonably well, but both sides of the net must be adjusted in unison, or the net is over-tensioned when one side is moved, thus two people are required. With only one person, the net must be adjusted the old-fashioned way, except that the cords need only be loosened, not reattached, since the attachment points themselves move. This mechanism is impractical for most installations, due to its expense. The telescoping portion has bearing runners guided by greased tracks in the fixed tube, and has a long rack of gears for the cranking pinion. Both the fixed and telescoping sections must be very strong to resist the lateral leverage of net tension and play stress, so the device is too heavy for mobile use. The greased bearing surfaces are not appropriate for sand courts.